y2038: elfcore: Use __kernel_old_timeval for process times

We store elapsed time for a crashed process in struct elf_prstatus using 'timeval' structures. Once glibc starts using 64-bit time_t, this becomes incompatible with the kernel's idea of timeval since the structure layout no longer matches on 32-bit architectures. This changes the definition of the elf_prstatus structure to use __kernel_old_timeval instead, which is hardcoded to the currently used binary layout. There is no risk of overflow in y2038 though, because the time values are all relative times, and can store up to 68 years of process elapsed time. There is a risk of applications breaking at build time when they use the new kernel headers and expect the type to be exactly 'timeval' rather than a structure that has the same fields as before. Those applications have to be modified to deal with 64-bit time_t anyway.

Arnd Bergmann committed 8 years ago

Commit e2bb80d1 parent 693737b6 files · +22 −22Browse files

Unified · Split

6 files

arch/mips/kernel/binfmt_elfn32.c +2 −2
arch/mips/kernel/binfmt_elfo32.c +2 −2
fs/binfmt_elf.c +6 −6
fs/binfmt_elf_fdpic.c +6 −6
fs/compat_binfmt_elf.c +2 −2
include/uapi/linux/elfcore.h +4 −4

arch/mips/kernel/binfmt_elfn32.c+2−2

@@ -100,7 +100,7 @@ jiffies_to_old_timeval32(unsigned long jiffies, struct old_timeval32 *value) · 99 unmodified lines
100	100	#undef TASK_SIZE
101	101	#define TASK_SIZE TASK_SIZE32
102	102
103		−#undef ns_to_timeval
104		−#define ns_to_timeval ns_to_old_timeval32
	103	+#undef ns_to_kernel_old_timeval
	104	+#define ns_to_kernel_old_timeval ns_to_old_timeval32
105	105
106	106	#include "../../../fs/binfmt_elf.c"

arch/mips/kernel/binfmt_elfo32.c+2−2

@@ -103,7 +103,7 @@ jiffies_to_old_timeval32(unsigned long jiffies, struct old_timeval32 *value) · 102 unmodified lines
103	103	#undef TASK_SIZE
104	104	#define TASK_SIZE TASK_SIZE32
105	105
106		−#undef ns_to_timeval
107		−#define ns_to_timeval ns_to_old_timeval32
	106	+#undef ns_to_kernel_old_timeval
	107	+#define ns_to_kernel_old_timeval ns_to_old_timeval32
108	108
109	109	#include "../../../fs/binfmt_elf.c"

fs/binfmt_elf.c+6−6

@@ -1489,18 +1489,18 @@ static void fill_prstatus(struct elf_prstatus *prstatus, · 1488 unmodified lines
1489	1489	* group-wide total, not its individual thread total.
1490	1490	*/
1491	1491	thread_group_cputime(p, &cputime);
1492		− prstatus->pr_utime = ns_to_timeval(cputime.utime);
1493		− prstatus->pr_stime = ns_to_timeval(cputime.stime);
	1492	+ prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
	1493	+ prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
1494	1494	} else {
1495	1495	u64 utime, stime;
1496	1496
1497	1497	task_cputime(p, &utime, &stime);
1498		− prstatus->pr_utime = ns_to_timeval(utime);
1499		− prstatus->pr_stime = ns_to_timeval(stime);
	1498	+ prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
	1499	+ prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
1500	1500	}
1501	1501
1502		− prstatus->pr_cutime = ns_to_timeval(p->signal->cutime);
1503		− prstatus->pr_cstime = ns_to_timeval(p->signal->cstime);
	1502	+ prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
	1503	+ prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
1504	1504	}
1505	1505
1506	1506	static int fill_psinfo(struct elf_prpsinfo psinfo, struct task_struct p,

fs/binfmt_elf_fdpic.c+6−6

@@ -1359,17 +1359,17 @@ static void fill_prstatus(struct elf_prstatus *prstatus, · 1358 unmodified lines
1359	1359	* group-wide total, not its individual thread total.
1360	1360	*/
1361	1361	thread_group_cputime(p, &cputime);
1362		− prstatus->pr_utime = ns_to_timeval(cputime.utime);
1363		− prstatus->pr_stime = ns_to_timeval(cputime.stime);
	1362	+ prstatus->pr_utime = ns_to_kernel_old_timeval(cputime.utime);
	1363	+ prstatus->pr_stime = ns_to_kernel_old_timeval(cputime.stime);
1364	1364	} else {
1365	1365	u64 utime, stime;
1366	1366
1367	1367	task_cputime(p, &utime, &stime);
1368		− prstatus->pr_utime = ns_to_timeval(utime);
1369		− prstatus->pr_stime = ns_to_timeval(stime);
	1368	+ prstatus->pr_utime = ns_to_kernel_old_timeval(utime);
	1369	+ prstatus->pr_stime = ns_to_kernel_old_timeval(stime);
1370	1370	}
1371		− prstatus->pr_cutime = ns_to_timeval(p->signal->cutime);
1372		− prstatus->pr_cstime = ns_to_timeval(p->signal->cstime);
	1371	+ prstatus->pr_cutime = ns_to_kernel_old_timeval(p->signal->cutime);
	1372	+ prstatus->pr_cstime = ns_to_kernel_old_timeval(p->signal->cstime);
1373	1373
1374	1374	prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
1375	1375	prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;

fs/compat_binfmt_elf.c+2−2

@@ -48,8 +48,8 @@ · 47 unmodified lines
48	48	#define elf_prstatus compat_elf_prstatus
49	49	#define elf_prpsinfo compat_elf_prpsinfo
50	50
51		−#undef ns_to_timeval
52		−#define ns_to_timeval ns_to_old_timeval32
	51	+#undef ns_to_kernel_old_timeval
	52	+#define ns_to_kernel_old_timeval ns_to_old_timeval32
53	53
54	54	/*
55	55	* To use this file, asm/elf.h must define compat_elf_check_arch.

include/uapi/linux/elfcore.h+4−4

@@ -53,10 +53,10 @@ struct elf_prstatus · 52 unmodified lines
53	53	pid_t pr_ppid;
54	54	pid_t pr_pgrp;
55	55	pid_t pr_sid;
56		− struct timeval pr_utime; /* User time */
57		− struct timeval pr_stime; /* System time */
58		− struct timeval pr_cutime; /* Cumulative user time */
59		− struct timeval pr_cstime; /* Cumulative system time */
	56	+ struct __kernel_old_timeval pr_utime; /* User time */
	57	+ struct __kernel_old_timeval pr_stime; /* System time */
	58	+ struct __kernel_old_timeval pr_cutime; /* Cumulative user time */
	59	+ struct __kernel_old_timeval pr_cstime; /* Cumulative system time */
60	60	#if 0
61	61	long pr_instr; /* Current instruction */
62	62	#endif